China has detained a Uighur scholar who has challenged the government on its treatment of ethnic minorities, The Wall Street Journalreported. Ilham Tohti, an economist at Minzu University of China, was detained after a raid on his Beijing home and has been accused of unspecified crimes. He has been critical of Chinese government policies in the western Xinjiang region, which is home to the predominantly Muslim Uighur minority population. He has been detained before and last year was prevented from leaving China to take up his position as a visiting scholar at Indiana University.